(MEDIA GENERAL) — Ever wonder how political scientists — and the campaigns, for that matter — determine how states will vote in presidential elections?

What demographics are they looking at? What statistics tell us who is likely to vote for whom?

Political scientists and pollsters do this by studying voter trends, which are carefully identified and studied to try to determine which personal affiliations and demographic qualifiers can help predict which way a specific person is likely to vote. Among those variables are race, religion, age and level of education, among many others.

How have those voter trends and, in turn, the Electoral College map changed over the years? How did the candidates’ and the political atmosphere tilt past elections? What voter trends are taking on greater importance when analyzing election outcomes?

How has the map changed since 1968?

The Red Sea: Incumbent Ronald Reagan easily wins reelection in 1984, winning 525 electoral votes over Democratic challenger Walter Mondale. Reagan’s 525 electoral votes are the most one candidate has ever received in a presidential election. (Courtesy: National Archives/Public Domain)

If you look at each electoral map from 1968 to 2012, you’ll find one notable difference: states now tend to be more partisan.

Regardless of candidate, red states will go red and blue states will go red. In years past, that wasn’t the case. In 1972, Republican Richard Nixon won in one of the largest landslides in American history, defeating Democrat George McGovern 520-17. McGovern only won Massachusetts and Washington D.C. Ronald Reagan and George H.W. Bush also had easy wins in 1980, 1984 and 1988. The map was almost entirely red!

Could you imagine a landslide of those proportions today? Political scientists consider President Barack Obama’s 2008 win over Sen. John McCain a resounding landslide (winning the popular vote 53-46 percent), and he only won 365 electoral votes. Those landslides seem like a near impossibility today.

What this means is most states have moved away from the middle. (Check out this map put together by The Wall Street Journal. It illustrates how states have shifted to the left or right.) Over the course of 20 years, California went from leaning Democrat to a firmly blue state. The Bible Belt moved from the middle to the darkest shades of red. States like Tennessee, Kentucky and West Virginia went from leaning Democrat in 1980 to firmly Republican by 2012. And they move further from the middle with each passing cycle.

Do we have new battleground states?

Florida, Ohio, Iowa and New Hampshire are perennial swing states, and in 2016, that is no different – all four are some of the closest races to call, according to 2016 polls. Since 1980, every winner has won at least three of these four swing states. But as the map evolves (as it always will), will new battleground states emerge?

The easy answer is yes. The map has always shifted. We’ve had perennial battleground states (Michigan, Pennsylvania) shift to strongholds for parties, and we’ve had states shift into perennial tossups. Colorado, Nevada and Virginia are three states that have trended back toward the middle – all three moving away from reliably Republican support. All three are considered tossups in the 2016 election, according to Real Clear Politics.

What key factors tend to tilt an election?

If the last 30 years are any indication, the election essentially boils down to two issues. When analyzing the incumbent party, is the sitting president popular and is the economy in good shape? Going through each election, if the answer to those two questions were positive, the incumbent’s party won.

1976 – Jimmy Carter edged incumbent Gerald Ford. The economy, though making progress, is still battling high inflation and unemployment. Ford also upset many Americans by pardoning his predecessor Nixon for his role in the Watergate scandal.

1980 – Ronald Reagan soundly defeats incumbent Carter. With the economy still sinking and the Iran hostage crisis hanging over Carter’s head, Reagan earned more electoral votes than any non-incumbent presidential candidate in the nation’s history.

1984 – Reagan bests challenger Walter Mondale. With the economy riding high, Reagan won over many independents and “Reagan Democrats” to win a record 525 electoral votes.

In this Oct. 15, 1992 file photo President George H.W. Bush looks at his watch during the 1992 presidential campaign debate with other candidates, Independent Ross Perot, top, and Democrat Bill Clinton, not shown, at the University of Richmond in Virginia. Many people believe Perot split the conservative vote and cost Bush another term in the White House, but some polls indicate that may not be true. (AP file)

1992 – Bush falls to challenger Bill Clinton. Bush’s popularity was sagging in 1992 as the economy lagged. Common belief is Ross Perot’s independent run cost Bush the election but polling indicates the opposite may have been true.

2000 – George W. Bush narrowly edges VP Al Gore. The 2000 election may be the only one to buck this trend and may prove to be the exception that makes the rule. The overall economy still was on solid footing in 2000, and despite the scandals surrounding Clinton’s second term, he still had approval ratings that hovered in the high-50s and low-60s through 1999 and 2000.

2004 – Incumbent Bush beats challenger John Kerry. Bush’s approval ratings already are on its downslope from its spike following the 9/11 attacks but are still hovering around 50 percent for most of 2004. The economy, though not performing as well as China and other emerging countries, is still holding together. If Kerry could have flipped Florida or Ohio, he would have won the election. Bush won Florida by five points and Ohio by two.

2008 – Barack Obama rolls past GOP nominee John McCain. With the economy squarely in a recession and Bush’s popularity at an all-time low, Obama won in a landslide.

2012 – Obama defeats challenger Mitt Romney. The economy in 2012 took a bit of a dip, but the recovery efforts in his first term were enough to keep Obama afloat. Despite partisan infighting, his approval ratings hovered around 50 percent, a stark improvement from Bush’s ratings in 2008.

What voter trends are emerging as key determining factors?

The candidates themselves always will play a major role in determining an election, but the past 20 years of evolving partisan politics have drawn clear lines on where parties stand on many issues.

Are you a white male member of the Mormon Church? You’re very likely to vote Republican. (This election, however, may be an outlier.) Are you a black woman over the age of 70? You’re very likely to vote Democrat.

White voters with a college degree appear to be shifting back toward the middle from the GOP. But in 2016, those without a college degree are moving further right. How much does Trump factor into those numbers? We will find out in the coming elections.

All demographics aside, nothing illuminates the party differences like race. Non-Hispanic Caucasians are much more likely to vote Republican, while blacks are much more likely to vote Democrat. One notable statistic that should be a cause for concern for Republicans is the expanding minority vote. With each cycle, approximately 500,000 Latinos join the voting rolls. Traditionally, Hispanics have voted with Democrats. Those numbers were heading closer to the middle under George W. Bush, but are quickly swinging back to the left under Obama. Polling for the 2016 election favors that move to continue further toward Democrats.

Erika Jaramillo, center, and others hold signs supporting Democratic presidential candidate Hillary Clinton during a Democratic National Convention watch party in San Antonio on Tuesday, July 26, 2016. Hispanics traditionally have voted Democratic since 1980. While those numbed started to move toward the middle for George W. Bush, Latino voting trends have swung back toward the left under Barack Obama and are expected to continue to the left in 2016. (AP file)

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